Filter



Patented Jan. 19, 1937 UNITED STATES PATENT OFFICE FILTER ApplicationJuly 15, 1935, Serial No. 31,361

2 Claims.

This invention relates to improvements in filters and more particularlyto means for assuring proper drainage for vacuum filter chambers orcompartments.

In rotary vacuum filters it is the general practice to provide at theperiphery of the drum a plurality of compartments or chambers havingfluid tight bottoms and sides, except for drainage outlets, an openworkbacking sheet or wire stretched over the tops of the compartments, andfilter cloth over said backing wire. If the backing wire be forced downtoo close to the bottom of a suction compartment, the drainage throughthis compartment will be interfered with or destroyed, and theefiiciency of the filter will be impaired accordingly. For avoidance ofsuch interference with drainage, use has heretofore been made ofdrainage devices, usually of wire, that are placed in said compartmentsto support the backing wire. Such drainage devices in prior use have,however, been comparatively easily crushed or deformed, for example bythe dropping of a tool thereon or in the event of the stepping thereonby a person engaged in repairing the filter.

The principal object of the present invention is to provide novel andadvantageous drainage devices which will be free of the aforesaiddefects. In preferred embodiments of the invention, such drainagedevices are made of relatively thin plates of corrosion-resisting metalformed, as by stamping, with raised portions to support the backingwires or sheets, and with perforations adapted to provide free drainagethrough the compartments. Preferably the raised portions of the drainageplates are provided by corrugating the plates, and the perforations areso arranged as to provide drainage passages not only through the tops ofthe ridges and bottoms of the intervening valleys or depressions, butalso at points intermediate said tops and bottoms.

One great advantage of the drainage devices of the present invention isthat they are strong enough to stand any ordinary rough usage withoutsubstantial damage.

Other objects, features and advantages will appear upon consideration ofthe following description and of the drawing, in which Fig. 1 is afragmentary elevational view of a rotary suction filter drum embodyingthe present invention, parts being broken away to show the underlyingstructure;

Fig. 2 is a section taken along the line 2-2 of Fig. 1;

Fig. 3 is a perspective view on a larger scale of the drainage plateillustrated in Figs. 1 and 2;

Fig. 4 is a plan view of a second form of drainage plate;

Fig. 5 is a section on the line 55 of Fig. 4; and 5 Fig. 6 is a planview of a third form of drainage plate.

Referring to Figs. 1 and 2, the reference character I0 designates arotary suction filter drum having a peripheral wall H, preferably ofcylin- 10 drical form, ends I2 of such diameter as to extend outwardlybeyond the cylindrical wall I], and dams or partitions 13 extending fromeither head l2 to the other thereby dividing the channel between theheads into a series of com- 15 partments.

Extending over the tops of the partitions l3 and from end to end of thedrum, is a foraminous backing sheet, or backing wire, l4 and outside ofthe backing wire is a filter cloth I5 which 20 may be of wire, cotton orany other suitable material. Preferably the arrangement is such that,although extending outside of the partitions l3 and of the backing wire[4, the filter cloth 15 does not project above the channel walls formed25 by the drum ends I2. At the bottom of each of the compartments, thecylindrical wall of the drum I0 is provided with one or more openings oroutlets 15a connected with a suitable vacuum producing means by means ofpipes 15b. 30

Installed in each compartment between adjacent partitions I3 is adrainage plate 16, preferably of corrosion resisting material such asbronze, constituting an embodiment of the present invention. Thisdrainage plate I6 is cor- 35 rugated, each of the ridges ll being formedwith a relatively long and straight incline at one side and a shorter,steeper and. substantially straight incline at the other side, and thevalleys or depressions l8 being narrow at their bottoms. 40 Theperforations IS in the drainage plate may be of any suitable shape andsize, but as illustrated in Fig. 3 each perforation is in the form of anelongated slot starting near the bottom of the long inclined side of oneridge I1, and extending 45 to the bottom of such long side, up the shortside of the next ridge and partially down the long side of said nextridge. It will be evident that this form of drainage plate will notinterfere to any substantial extent with the drainage and at the 50 sametime will resist very strongly any force tending to deform it. Eachdrainage plate l6 may be secured in'- place in any suitable manner as bymeans of screws threaded into the cylindrical Wall. 55

The second form of drainage plate [6a, illustrated in Figs. 4 and 5, isvery similar to the drainage plate l6 of Fig. 3 but has rounded ridgesIla and rounded depressions 18a and the slots or perforations [9a. arerounded at their ends In Fig. 6, there is illustrated a third form ofdrainage plate lBb which difiers principally from the other forms ofplates by the shape of its perforations l9b which are round and arrangedin sets of three rows, one row in a depression or valley and the othertwo rows on an adjacent ridge.

Although, as illustrated, the bottoms of all the compartments are partsof a cylindrical casing and the drainage plates are curved accordingly,it should be understood that the bottoms of the compartments may be ofother shapes and the drainage plates may be changed accordingly. Alsothe present invention may as well be applied to a filter in which theliquid to be filtered is introduced to the interior of the drum, as tothe illustrated form of drum which is designed to be partiallysubmerged.

It should be understood that various changes may be made and thatcertain features may be used without others without departing from thetrue scope and spirit of the invention.

Having thus described my invention, I claim:

1. In a vacuum filter comprising an open top compartment having vacuumconnections and filtering means stretched across the top of saidcompartment, a drainage plate in said compartment supporting saidfiltering means, said drainage plate having corrugations providingalternate ridges and valleys and elongated slots each starting on oneside of one of said ridges and extending over the crest of the ridge,down the other side thereof to the bottom of the next valley and part ofthe way up the side of the next ridge.

2. In a vacuum filter comprising an open top compartment having vacuumconnections and filtering means stretched across the top of saidcompartment, a drainage plate in said compart ment supporting saidfiltering means, said drainage plate having corrugations providingvalleys and intervening ridges each formed with a relatively longstraight incline at one side and a steeper relatively short straightincline at the other side of the ridge, said drainage plate also havingslots each beginning at a point part way up the long incline at one sideof a ridge and extending over the top of the ridge, down the shortincline of this ridge to the bottom thereof and part way up the longincline of the next ridge.

WILLIAM RAISCH.

